Photographic elements containing bischloroacylamido hardening agents



iinite States This invention relates to the hardening of photographiclayers, particularly of silver halide emulsion layers which contain as acolloidal carrier material a protein derivative, particularly gelatin.

Photographic materials are treated with photographic processingsolutions which have different pH values and diiferent temperatures. Itis, therefore, extremely important to use photographic products withcolloidal layers which when compared with pure gelatin are moreresistant to water, swell less and have a higher melting point. For thisreason, the gelatin layers must be hardened without depriving them oftheir water permeability. A large number of publications haverecommended whole series of compounds and classes of compounds ashardening agents. The following classes can be distinguished: Metalsalts such as chromium, aluminum or Zirconium salts; aldehydes andhalogen containing aldehydes such as formaldehyde, dialdehydes (glyoxal)and mucochloric acid; 1,2 and 1,4-diketones such ascyclohexanedione-l,2; quinone; chlorides of di basic organic acids;dianhydrides of tetracarboxylic acids; compounds with several reactivevinyl group such as vinylsulfone or acrylamide; compounds with at leasttwo easily splitable heterocyclic rings such as ethylene oxide andethyleneamine; and polyfunctional esters of methanesulfonic acid.

Most of these hardening agents are photographically active and for thisreason cannot be used with a large variety of photographic emulsions.Besides, the metal salts increase the brittleness of the layers, whereasthe aldehydes react with various types of color formers present in thecolor emulsion layers and cause color fog. Several of the diketones anddialdehydes color the colloidal layers and are, therefore, unsuitable.Moreover, many hardening agents tend to fog the emulsion on prolongedstorage or to decrease the sensitivity. The anhydrides and the acidchlorides have the inherent disadvantage of lowering the pH of theemulsion, thus requiring an adjustment of the pH with an alkali. In manyinstances, the hardening agents increase the viscosity of the coatingsolution to an alarming degree. Other hardening agents suffer from thedisadvantage that they become active only after prolonged storage. Inthis manner, these hardening agents change the sensitometriccharacteristics of the layer in an uncontrollable manner. One refers tothis effect as after-hardening.

It is among the objects of the present invention to provide novelhardening agents for photographic layers, particularly gelatin andgelatin silver halide emulsion layers, thus providing products whichhave improved physical and photographic properties. Other objects willbe apparent from the following description.

We have found that the products obtained by the re action of aliphatic,aromatic or heterocyclic diamines with a-chloroacyl chlorides serve asvery useful hardening agents. When these reaction products are added togelatin solutions or liquid gelatin silver halide emulsions, theyincrease the melting point of the coated layers without causing anyadverse eifects such as fog, desensitization or loss of contrast. Thematerials obtained are stable and do not deteriorate during storage dueto after- 3,i?4,8bl. Patented Mar. 23, 1955 ice In this formulae R R Rand R which may be alike or different represent hydrogen or lower alkylgroups such as methyl, ethyl, or propyl; n is a positive integer rangingfrom 1 to 7; X and X together represent the carbon atoms necessary tocomplete a fully hydrogenated 5 or 6 membered heterocyclic nucleus suchas a piperazine or pyrazolidine; and Y and Y together represent theatoms necessary to complete an aromatic nucleus of the benzene serieswhich may be further substituted by a suitable group such as a carboXygroup to increase the water solubility of the hardening agent.

These hardening agents can be readily prepared by reacting in an aqueousalkaline solution, an aliphatic, aromatic or heterocyclic diamine withthe chloride of an ot-chlorocarboxylic acid. The separation andpurification of the reaction products does not offer any difiicultiesbecause the compounds precipitate from the solution and need only to bepurified by recrystallizing the precipitate.

Among the diamines which can be used in the reaction are the following:

Hydrazine N,N'-dimethylhydrazine Methylenediamine EthylenediaminePropylenediamine Tetramethylenediamine Pentamethylenediarnine.l-iexamethylenediamine 1,2-phenylenediamine 1,4-phenylenediamine Piperazine Pyrazolidine Among the chlorides of a-chlorocarboxylic acidswhich can be used in the preparation of the novel hardening agents are:a-chloracetyl chloride, oc-ChlOlOPIOPiOIlYl chloride andct-chlorobutyryl chloride.

These compounds are used advantageously in photographic silver halidegelatin emulsion layers, as well as in backing layers, non-curlinglayers, protective layers, filter layers, and other auxiliary layerswhich contain gelatin or other related proteins. Our hardening procedurereduces swelling, as well as the solubility of gelatin in the desiredmanner. A further advantage resides in the fact that the hardened layersdo not become brittle. In this respect, they are superior to thetrifunctional hardening agents which provide a three-dimensional bondingand result, therefore, in layers which are inherently more brittle. Thehardened layers show also in the moistened state a good abrasionresistance and a surprisingly low swelling height. In general, there isvery little after-hardening because maximum hardening is reached withina few days.

A great advantage of the hardeners of this invention resides in thefeature that they will not react with any color formers which arepresent in multilayer color materials. Consequently, they can also beused in multilayer materials having incorporated in the emulsions colorformers which are fast to diffusion.

Furthermore, it was observed that the compounds do not only harden thelayers but improve the adhesion of the several over-coated layers inmultilayer materials. The danger of separation of the layers in the wetstate during the processing and drying is, therefore, reduced.

The hardening agents are added to the photographic coating preparationsin the form of a solution in a suitable water-miscible organic solventsuch as methanol, ethanol, dioxane, dimethylformarnide and the likeprior to coating. Neither the viscosity nor the pH of the coatingsolutions are altered by this technique. The amounts of hardening agentsadded depend on the desired effect. In general, from 1.0 to 20.0 gramsof hardening agents per kilogram of dry colloidal carrier material suchas gelatin are sufiicient. One thereby obtains layers with high meltingpoints. The action of the hardening starts only after the drying of thelayer.

The action of the hardening agents can be explained on a hypotheticalbasis by assuming that the a-chlorine atom is rendered more labile bythe proximity of the CO group and is readily split off; so that theremaining part of the hardener molecule reacts with the amino group ofone or several gelatin molecules as indicated by the following formula:

Z Protein E Z Protein It should be understood, however, that theinvention is not based on the hypothetical formulation. There are agreat number of compounds which can be used as hardening agents inaccordance with this invention. The following examples are illustrative:

( 1) Bis-chloroacetylhydrazine Preparatin.40 grams of hydrazine hydrate(25%) and grams of potassium hydroxide are dissolved in 50 millilitersof water. This resultant solution is cooled to 0 to C. and 30milliliters of chloroacetyl chloride are added dropwise with stirring.At the completion of the reaction, the pH of the mixture is adjustedwith sodium hydroxide to a value between 7 and 8. Stirring is continuedfor one-half hour. The precipitate is filtered, washed and dried. Yieldof crude product is grams. The product is purified by recrystallizationfrom methanol and has then a melting point of 165 to 167 C.

(2) Bis-chloroacetyl-N,N'-dimethylhydrazine Preparation.--In analogy tothe above procedure except that dimethylhydrazine was used as thestarting material; M.P. 124 C.

(3) Methylene-bis-chloroacetamide Preparati0n.Annalen, vol. 343, page284; M.P. 174 C.

Prepar'ation.]. Biol. Chem, vol. 21, page 151; M.P. 174176 C.

(5 Bis-chloroacetyl-N,N'-dimethylethylenediamine ClCH -C ONCH2CH2NCO-CH2C1 H3 H3 Preparation.1n analogy to the procedure described in J.Biol. Chem, vol. 21, page 151, except that N,N-dimethylethylenediaminewas used in place of ethylenedlamine; M.P. -132 C.

(6) Bis-chloroacetylpiperazine CHg-OH N-C OGH2C1 GH -CHPreparation.Hopper-Seyler, vol. 144, page 220; M.P. l37-138 C.

(7) Bis-chloroacetyl-tetramethylenediamine Preparati0n.-44 grams oftetramethylenediarnine are added to a solution of sodium hydroxide in200 milliliters of water. The mixture is cooled to a temperature of 5C., stirred and 112 grams of chloroacetyl chloride are added dropwisewith stirring. The pH is adjusted to a value between 7 and 8 by addingthe necessary amount of 10% sodium hydroxide solution. Stirring wascontinued for one-half hour and then the substance which hadprecipitated was filtered off and washed with water. Afterrecrystallization from alcohol, 42 grams of the pure compound wasobtained which had a melting point of 134 C.

(8) Bis-chloroacetyl-l,'2-phenylenediamine 4 carboxylic acidIIIlEP-CO-OHzCl Preparation-15.2 grams of 3,4-diaminobenzoic acid areadded to a solution of 12 grams of sodium hydroxide in 200 millilitersof Water. The resultant mixture was cooled to 5 C. and 28.2 grams ofchloroacetyl chloride are added dropwise with stirring. The pH of themixture was adjusted with sodium hydroxide to a value between 9 and 10.Stirring was continued for one-half hour and then the solution wasacidified with dilute sulfuric acid. The substance which precipitatedwas separated, washed and recrystallized from ethanol. Yield 16 grams;M.P. 231 C.

(9) Bis-a-chloropropionylpiperazine CHZ OH2 N-CO-CHCl-C'H;

Ora-CH2 Preparation-44 grams of piperazine are added to 200 millilitersof a 10% sodium hydroxide solution. The solution is cooled to 5 C. and128 grams of Z-chloropropionyl chloride are added dropwise withstirring. The pH is adjusted to a value between 7 to 8 with dilutesodium hydroxide at the end of the addition period. The product wasfiltered off under suction and washed thoroughly with water. Afterdrying it was recrystallized from a small amount of methanol. Yield 30grams; M.P. to 162 C.

The emulsion layers and intermediate layers which are hardened with ournovel hardening agents can be coated on all known supports such asglass, paper, cellulose esters or other film forming synthetic polymers.The general composition of the coating solutions used for thepreparation of these layers does not need to be changed because theadhesion of these layers is not adversely influenced by the hardening.In some cases, the.

adhesion is even improved through the use of the novel hardening agents.Similarly, the sensitizing procedure or other conventional methods ofpreparing the emulsions can be retained without change. The hardeningagents described herein can be combined with previously known hardeningagents if special efl ects are desired.

The advantages of our novel hardeners are especially pronounced whenthey are used in color materials including color films and papers whichcontain color formers fast to diffusion. Such materials are preparedaccording to the methods described in US. Patents 2,179,- 228,2,179,239, 2,186,849 and 2,200,187 and consist of several integralemulsion layers coated on a clear cellulose ester film base, opaque baseor paper. Each of the emulsions is sensitized to one of the primarycolors of light, namely blue, green, and red. Usually, the top layer isblue sensitive, the middle layer is green sensitive, and the bottomlayer is red sensitive. Each of the three silver halide emulsion layerscontains dye-forming compounds fast to diffusion.

During the development of the silver image by an aromatic aminodeveloping agent, these dye-forming compounds unite with the oxidationproducts of the developing agent to form an azornethine or indoanilinedye. Alternatively, the emulsion layer may be free from color formers inwhich case the film is processed with the color formers in the colordevelopers by the selective second exposure and color development methodas described in US. Patent 1,897,866, 1,900,870, 1,928,709, and1,980,941.

Multicolor film in which each element bears a color yielding layercomprising a hydrophilic film-forming synthetic polymer containing aplurality of hydroxyl groups and having a plurality of color componentsand, in addition, containing light-sensitive silver salts in describedin US. Patents 2,397,864, 2,397,865, 2,397,866, and 2,397,867.

Materials in which the developed picture is a phenazonium dye imageformed by development with a 1,2,4- triaminobenzene developer aredescribed in US. Patents 2,486,440, and 2,570,116.

While the following examples describe in detail the methods foraccomplishing the aforestated objects, it is to be understood that theyare given merely for the purpose of illustration and are not to beconstrued as limiting the scope of the invention.

Example I To 1 kilogram of a silver chlorobromide emulsion which isready for coating and contains about 65 grams of gelatin, there wasadded 1.5 grams of bis-chloroacetyl- N,N-di1nethylethylenediaminedissolved in methanol. The addition of this hardening mixture does notincrease the viscosity and does not change the pH which is preferablykept between a range of 6.0 to 8.0. The emulsion is coated on barytapaper. After the usual drying and storing for 48 hours at a temperatureof 45, it was noted that the layer had a melting point of 100 C. Thehardening is not influenced by the pH in a pH range of 6.0 to 8.0 andthe photographic properties of the emulsions are not changed. Afterdevelopment, when conventionally hardened emulsion layers are usually ina highly swelled and tacky state, the swelling is minimal of ourhardened layers and is negligible; besides the layers show no tackinessand good abrasion resistance. The extent of hardening in relation to theadded amounts of hardening agents is shown in the following table:

Added amount of hardening agent relative to the dry weight of thegelatin. percent O Melting point of the layer after storage for 48 hoursat 45 C 37 usual manner is coated with a blue-sensitive silver bromideemulsion which contains per one liter of solution:

45 grams of silver bromide, 70 grams of gelatin, and 11 grams of a colorformer of the following formula:

COONa The coating solution contains as the hardening agent 1.4 grams ofbis-chloroacetyl-N,N'-dimethylethylenediamine dissolved in methanol. Thecoated layer is dried and stored for 48 hours after which time it showeda melting point of C. After completed color processing, the layer showedgood adhesion to the support and contained a stain-free yellow dyeimage. The photo graphic properties of this emulsion including colordensity, speed and contrast were the same as those of an unhardened typeemulsion.

Example III The light-sensitive material prepared in accordance withExample II was overcoated with a red-sensitive silver chloride emulsionwhich contains per 1 liter of solution:

33 grams of silver chloride, 72 grams of gelatin, and 14 grams of acolor former having the following formula:

The coating solution contained 3 grams of the hardening agentbis-chloroacetyl-ethylenediamine. After coating, drying and storage, themelting point of the layer was determined as being above 90 C. Theadhesion of the two color emulsion layers was noticeably improved by ourhardening agent when compared with conventional hardening agents.

Example IV A subbed cellulose acetate film support was coated with 1kilogram of a gelatin solution which contained approximately 30 grams ofgelatin together with an antihalation dye and 1 gram of the compoundbis-chloroacetyl-1,2- phenylenediamine-4-carboxylic acid dissolved inethanol. After drying and storage, the backing layer had a melting pointabove C. This layer showed no tendancy to swell and had a very highresistance to abrasion in its wet state.

Example V Example IV was repeated with the exception that the hardeningagent used was 1 gram of bis-chloroacetyl-N, N'-dimethylhydrazine. Thebacking layer obtained therefrom shows very little swelling and a highabrasion resist ance in the wet state.

Example VI '7 We claim: 1. A photo-sensitive element comprising asupport and a gelatin silver halide emulsion coated thereon, saidemulsion containing a hardening amount of a bis-chloroacylamidohardening agent selected from the group of compounds having thefollowing general formulae:

R1OHC o-N-c'n cn-N o o-cn-Ri I 1 -Yr 01 wherein R R R and R are membersselected from the group consisting of a hydrogen atom and lower alkylgroups, n represents a positive integer ranging from 1 to 7; X and Xrepresent the carbon atoms necessary to complete a hydrogenatedheterocyclic nucleus; and Y and Y represent the carbon atoms necessaryto complete an aromatic nucleus of the benzene series.

2. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing a hardeningamount of a compound having the following formula:

CH CH3 3. A photo-sensitive element comprising a support and a gelatinsilver halide emulsion coated thereon, said emulsion containing ahardening amount of a compound having the following formula:

4. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing a hardeningamount of a compound having the following formula:

5. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing in addition toa color former fast to diffusion capable of forming upon developmentwith a primary amine developing agent, a dye image selected from thegroup consisting of azomethine, indoaniline and phenazonium dye images,a hardening amount of a hardening agent selected from the group ofcompounds having the following general formulae:

wherein R R R and R are members selected from the group consisting of ahydrogen atom and lower alkyl groups, n represents a positive integerranging from 1 to 7; X and X represent the carbon atoms necessary tocomplete a hydrogenated heterocyclic nucleus; and Y and Y represent thecarbon atoms necessary to complete an aromatic nucleus of the benzeneseries.

6. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing in addition toa color former fast to diffusion capable of forming upon developmentwith a primary amino developing agent, a dye image selected from thegroup consisting of azomethine, indoaniline and phenazonium dye images,a hardening amount of a hardening agent of the following formula:

7. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing in addition toa color former fast to diffusion capable of forming upon developmentwith a primary amino agent, a dye image selected from the groupconsisting of azomethine, indoaniline and phenazonium dye images, ahardening amount of a hardening agent of the following formula:

8. A photo-sensitive element comprising a support and a gelatin silverhalide emulsion coated thereon, said emulsion containing in addition toa color former fast to diffusion capable of forming upon developmentwith a primary amino development agent, a dye image selected from thegroup consisting of azomethine, indoaniline and phenazonium dye images,a hardening amount of a hardening agent of the following formula:

IITH-C O-CHzCl 9. A photo-sensitive element comprising a support andcoated thereon a gelatin silver halide emulsion layer and a gelatinlayer, at least one of these gelatin layers containing a hardeningamount of a bis-chloroacylamido hardening agent selected from the groupof compounds having the following general formulae:

wherein R R R and R are members selected from the group consisting of ahydrogen atom and lower alkyl groups, n represents a positive integerranging from 1 to 7; X and X represent the carbon atoms necessary tocomplete a hydrogenated heterocyclic nucleus; and Y and Y represent thecarbon atoms necessary to complete an aromatic nucleus of the benzeneseries.

10. A photo-sensitive element comprising a support carrying a gelatinsilver halide emulsion and a gelatin layer coated thereon, at least oneof these gelatin layers containing a hardening amount of a compoundhaving the following formula:

11. A photo-sensitive element comprising a support carrying a gelatinsilver halide emulsion and a gelatin layer coated thereon, at least oneof these gelatin layers containing a hardening amount of a compoundhaving the following formula:

3,174,861 9 i@ 12. A photo-sensitive element comprising a supportReferences fired by the Examiner carrying a gelatin silver halideemulsion and a gelatin UNITED STATES PATENTS layer coated thereon, atleast one of these gelatin layers r containing a hardening amount of acompound having the 3/61 Levme 11 FOREIGN PATENTS following formula: 5

T 787,400 12/57 GreatBritain.

NORMAN G. TORCHIN, Primary Examiner.

1. A PHOTO-SENSITIVE ELEMENT COMPRISING A SUPPORT AND A GELATIN SILVERHALIDE EMULSION COATED THEREON, SAID EMULSION CONTAINING A HARDENINGAMOUNT OF A BIS-CHLOROACYLAMIDO HARDENING AGENT SELECTED FROM THE GROUPOF COMPOUNDS HAVING THE FOLLOWING GENERAL FORMULAE: